Riveters powered by electricity (hereinafter, referred to as electric riveters) have been conventionally provided as a riveter that is used when riveting two or more members. Such an electric riveter includes an actuator for withdrawing a mandrel inserted through a rivet, a drive unit for driving the actuator, and a housing internally provided with the actuator and the drive unit.
The actuator includes a cylindrical cover having a distal end and a proximal end, in which the proximal end is coupled to the housing, a cylindrical jaw case that has a distal end and a proximal end and is provided inside the cover concentrically therewith so as to be movable along the center of the cover, a nozzle that is provided at the distal end of the cover and includes a rivet insertion hole formed concentrically with the jaw case, and a jaw that is provided inside the distal end of the jaw case and is configured to be capable of clamping the mandrel. Thus, the actuator is configured to allow the mandrel inserted through a rivet shaft insertion hole to reach the jaw within the cover (jaw case).
The drive unit includes an electric motor having an output shaft, and a drive transmission mechanism that transmits the driving force of the electric motor to the actuator. The drive transmission mechanism includes a feed screw mechanism that moves the jaw case within the cover. The feed screw mechanism includes an internally threaded member and an externally threaded member that is screwed into the internally threaded member concentrically therewith.
One of the internally threaded member and the externally threaded member of the feed screw mechanism is coupled directly or indirectly to the proximal end of the jaw case. The other of the internally threaded member and the externally threaded member of the feed screw mechanism of the drive transmission mechanism is coupled directly or indirectly to the output shaft of the electric motor concentrically therewith. This allows the other of the internally threaded member and the externally threaded member to rotate in the drive transmission mechanism by receiving the driving force of the electric motor. Then, the one of the internally threaded member and the externally threaded member moves in a direction in which the center line of the externally threaded member extends. Accordingly, the jaw case is configured to move in the same direction as the one of the internally threaded member and the externally threaded member moves by the driving force of the electric motor. Similarly, the jaw provided inside the jaw case is also configured to move in the same direction as the one of the internally threaded member and the externally threaded member moves.
The housing has a handle having a first end and a second end on the opposite side of the first end, and a drive housing unit that houses the drive unit and is connected to the first end of the handle. The handle is formed so that the center line extending from the first end to the second end (or from the second end to the first end) serves as the center of gripping when an operator grips the handle. The handle is provided with a trigger switch for switching between supplying and cutting off power to the electric motor. The trigger switch is arranged within a region of the handle where the operator grips it.
The drive housing unit of the housing houses the feed screw mechanism (the internally threaded member and the externally threaded member) so that the axial cores of the internally threaded member and the externally threaded member extend in a direction intersecting a direction in which the center line of the handle (the center of grip) extends. Further, the drive housing unit of the housing also houses the electric motor so as to be capable of transmitting the driving force to the feed screw mechanism.
The proximal end of the cover is coupled to the drive housing unit of the housing so as to be concentric with the feed screw mechanism housed therein. That is, the drive housing unit has the first end and the second end on the opposite side of the first end in the direction intersecting the direction in which the center line of the handle (the center of grip) extends. The proximal end of the cover is coupled to the first end of the drive housing unit so as to be concentric with the feed screw mechanism housed therein.
In such an electric riveter of this type, an operator operates the trigger switch in the state where the mandrel inserted through the rivet is inserted through the rivet shaft insertion hole when crimping the rivet. This causes the feed screw mechanism to receive a driving force from the electric motor. Then, the jaw clamping the mandrel moves from the distal end side of the cover to the proximal end side of the cover. Following this, the rivet is crimped, and the mandrel is withdrawn from the rivet (see Patent Literature 1).
Meanwhile, since it is cumbersome to remove a mandrel withdrawn from a rivet by hand each time when crimping the rivet, an electric riveter including a mandrel collector that continuously collects mandrels withdrawn from rivets is provided (see Patent Literature 2). In such an electric riveter, the mandrel collector includes a pin collection path having a first opening end and a second opening end on the opposite side thereof, and a collection tank that houses mandrels therein.
The pin collection path is concentric or substantially concentric with the jaw case and the feed screw mechanism. That is, the pin collection path passes through the externally threaded member of the feed screw mechanism so as to extend along the center of the jaw case and the feed screw mechanism. The pin collection path opens at the first opening end into the jaw, and opens at the second opening end into the second end of the drive housing unit. Thus, the collection tank is coupled to the second end of the drive housing unit, thereby allowing the internal space of the collection tank to communicate with the second opening end of the pin collection path.
Accordingly, in the electric riveter of this type, the electric motor is arranged between the feed screw mechanism of the drive unit and the gripping position of the handle, so as to allow the second opening end of the pin collection path to open. That is, in the electric riveter of this type, it is impossible to allow the second opening end of the pin collection path to open, if the actuator (feed screw mechanism) and the electric motor are arranged in the same raw. Therefore, the electric motor of the electric riveter of this type has an output shaft that extends in parallel to the feed screw mechanism and is located between the feed screw mechanism and the gripping position of the handle in a direction in which the center of grip extends.
Further, the drive unit of the electric riveter with the aforementioned configuration further includes a gear mechanism that transmits the driving force of the electric motor to the internally threaded member. The gear mechanism includes a first gear wheel that is coupled to the output shaft of the electric motor, and a second gear wheel that is attached to the other of the internally threaded member and the externally threaded member. The first gear wheel and the second gear wheel mesh with each other directly or via an intermediate gear wheel.
In the electric riveter with the aforementioned configuration, the proximal end of the jaw case is coupled to the externally threaded member of the feed screw mechanism. Thus, the electric riveter with the aforementioned configuration is configured so that the driving force of the electric motor is transmitted to the one of the internally threaded member and the externally threaded member via the gear mechanism.
Therefore, as the other of the internally threaded member and the externally threaded member rotates in conjunction with the electric motor, the jaw moves together with the one of the internally threaded member and the externally threaded member. This causes the mandrel to be withdrawn from the rivet after the rivet is crimped. Then, when the jaw releases the clamping of the mandrel, the mandrel is collected into the collection tank, passing through the pin collection path. Accordingly, the electric riveter with the aforementioned configuration makes it possible to continuously crimp a plurality of rivets, without the need to remove a mandrel each time when crimping a rivet.